Ran into this issue tonight when trying to deploy some code to the Netduino Plus and found the solution on http://www.ghielectronics.com/forum/index.php?topic=3035.0. Summary: If you see “DebugPort.GetDeviceProcess() called with no argument” show up, then try to switch over to deploying to the emulator and then back to the Netduino.

Thanks – I was pulling my hair out on this one. I had the USB correctly selected and could not deploy. I switched to emulator and did a build. When I switched back to USB and did a build followed by debug the problem went away.